This invention relates to the accurate volumetric metering of thixotropic type battery pastes onto a suitable grid for preparation of battery plates.
In my related commonly assigned U.S. Pat. No. 3,814,628 I disclosed a method of uniformly distributing viscous thixotropic paste onto a substrate by (a) continually pumping and circulating the battery paste with a first pump through a substantially closed loop conduit system; (b) diverting the flow of a portion of the circulating paste away from the closed loop with the aid of a second pump of positive displacement type, preferably of the progressing cavity type; and (c) metering the diverted paste with the second pump at a substantially constant volumetric flow rate to a discharge means and thereby applying the diverted paste onto the substrate. The method of this patent has proved to be quite beneficial, offering significant advantages over previous methods which typically forced excess paste onto a substrate and then using a screed or doctor blade to remove the excess. By not applying the paste at a predetermined volumetric flow rate the final density of the electrode plates varied depending upon the grid geometry and thus presented a drawback.
The primary object of the present invention is to provide a system for metering battery paste extremely accurately and which may be used to paste individually sized grids or, less preferably, a continuous length of grid which is later sized.